Pressure device for a flat bed knitting machine



Aug. 21, 1962 w. BRAM 3,049,900

PRESSURE DEVICE FOR A FLAT BED KNITTING MACHINE Filed Feb. 15, 1960 3 Sheets-Sheet 1 w. BRAM 3,049,900 PRESSURE DEVICE FOR A FLAT BED KNITTING MACHINE Aug. 21, 1962 5 Sheets-Sheet 2 Filed Feb. 15, 1960 Aug. 21, 1962 w. BRAM 3,049,900

PRESSURE DEVICE FOR A FLAT BED KNITTING MACHINE Filed Feb. 15, 1960 3 Sheets-Sheet 3 Q &

3,049,900 Patented Aug. 21, I952 3,049,900 PRESSURE DEVICE FOR A FLAT BED KNITTING MACHINE Walter Bram, Dietikon, Zurich, Switzerland, assignor to Paliz-Holding A.G., Zug, Switzerland, a corporation of Switzerland Filed Feb. 15, 1960, Ser. No. 8,805 Claims priority, application Switzerland Feb. 17, 1959 7 Claims. (Cl. 66-60) The present invention relates to flat bed or straight knitting machines and more particularly to an improved pressure device movable with a cam device for advancing and retracting the knitting needles.

It has been proposed to use in conventional knitting machines two pressure devices, one for each direction of movement of the cam device on which they are rotatably supported to swing on a common axis. The latter must be located substantially in the middle of the cam which advances the needles through a knocking-over comb. In these conventional arrangements, the automatic turning of the pressure devices is not performed absolutely reliably and additional means must be provided to ensure proper turning of the devices.

It is an object of the invention to provide a pressure device for a fiat bed knitting machine which device turns reliably to the desired position whenever the direction of movement of the cam device is reversed. The pressure device according to the invention comprises two independent pressure elements which are spaced in the longitudinal direction of the knitting machine and are individually rotatably supported by a support which is removably connected to the cam device. The pressure elements rotate in a vertical plane which is parallel to the direction of movement of the cam device and adjacent to the knocking over comb. The axes of rotation of the pressure elements are at right angles to the aforesaid plane. Each pressure element includes a resilient arm for guiding the knitting and other purposes to be described below which arm extends downward below the plane of the needle bed when the respective pressure element is beyond the knitting and the needles thereat are in retracted position. In a knitting machine having two needle beds and two combs placed in parallel relation, the plane in which the pressure elements are rotatable extends between the two combs and the arms of the pressure elements are between the two combs when the pressure elements are not turned to their idle positions.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in connection with the accompanying drawing, in which:

FIG. 1 is a side view of a portion of a knitting machine, looking in the direction of arrow 1 in FIG. 2, one of the needle beds shown in FIG. 2 being omitted.

FIG. 2 is a cross sectional view of the knitting machine, the section being made along line II-II in FIG. 1.

FIG. 3 is a plan of a pressure element according to the invention and a diagrammatic representation of the course of movement of the needles.

FIG. 4 is a side view of a modified pressure element.

FIG. 5 is a plan view of a modified part of a pressure element.

FIG. 6 is a plan view of another modification of a part of a pressure element.

FIG. 7 is a side view of a portion of a knitting machine provided with a modified pressure device according to the invention.

FIG. 8 is a plan view of a modified pressure arm.

FIG. 9 is a side view of a modified member of the pressure device shown in FIG. 7.

The straight knitting machine shown in FIGS. 1 and 2 has two needle beds 1 and 2 which are secured to a frame at an angle in the usual way which is not shown here in detail. A number of latch needles 3, placed side by side, are mounted on each of these needle beds in such a way that they are free to move longitudinally, only the needles in the rear needle bed being shown. The movements of the needles are controlled in the usual manner by cams on a carriage 4, of which only parts are shown in FIG. 2. As is usual the carriage 4 can be moved at a right angle to the needles and is provided with mirrorsymmetric cams, one of which advances the needles in the manner indicated by a dash-dot line 5 in FIG. 3, upon movement of the carriage in the direction of the arrow A in FIGS. 1 and 7, from an initial position 5a in the rear of corresponding knocking-over combs 6 and 7, one of which is associated with each needle bed, through the respective knocking-over comb to a front position 5 b, in order to push back the last knitted stitch and at the same time to open the latches. Thereupon the needles are pulled back into a position 50 in which the latches are still open and the yarn for the new stitches is inserted into the hooks of the knitting needles and finally back into the rest position 5a behind the respective knocking-over comb. When the carriage is moved in the opposite direction, the second cam controls the movement of the needles. A suitable cam system is disclosed in Patent No. 2,958,214.

A support means including a mounting bracket 8 to which a pressure device 10 is removably secured by means of a bolt 9, is connected to the carriage or cam device 4. The pressure device includes two base plates 12 and 13 connected by a crosstie 11. Each plate is provided with a pivot pin 14, 15 extending at right angles from the plates 12 and 13 and to the direction of movement of the cam device. The pins 14, 15 individually pivotally support members 18 and 19 forming part of pressure elements 16 and 17, respectively. Pressure arms 20 and 211 are individually bolted to the members 18 and 19. The two pressure elements 16 and 17 have the same shape, but are placed on the pins 14, 15 in mirror-symmetric relation. Each arm 20 and 2.1, is bent to form three parts: a securing part 20a, 21a, a holding down part 20b, 21b and a retaining part 200, 210. The holding down part is approximately coextensive with the part of the cam device which advances the needles 3 from the rest position 5a through the knocking-over comb 6, while the re taining part is so shaped that its end extends beyond the part of the cam device which returns the needles from the position 50 to the rest position 5a behind the knocking-over comb. The pivoting of the elements 16 and 1.7 about pins 14 and 15 is restricted by stops 22 and 23, respectively, which engage in corresponding recesses 24a and 2417 or 25a and 25b, depending on the direction of swinging of the elements 16 and 17.

The elements 16 and 17 may be made of a single piece of metal or plastic.

When the machine is idling, i.e..no knitting is in progress, the two elements 16 and 17 remain in the position indicated by dash-dot lines in FIG. 1 with reference to piece 17. In this balanced position, the arms or rather their retaining parts 20c and 21c extend below the plane of the needle bed which is schematically shown in FIGS. 1 and 7 by a dash-dot line 26. If knitting is begun and the carriage moves in the direction of arrow A in FIG. 1, the retaining part 200 of arm 20 of the leading element 16 engages the fabric suspended on the two rows of needles in the two beds, element 16 being swung into the position shown in solid lines in FIG. 1 in which the recess 24a of member 18 engages the stop 22. The holding down part 20b diagonally intersects the needle plane 26 like a plough and the retaining part 20c, which is resilient, rests on the fabric parallel to and below the needle bed plane 26. In FIG. 1 the position which part 20c would occupy if, during idling, element '16 were swung into the position shown in solid lines, is indicated by dash-dot lines with reference to piece 16. This shows that part 20c exerts a downward pressure on the fabric, if there is a fabric. The trailing element 17 is swung in anti-clockwise direction until the notch 25a engages the stop 23. In this position, the whole element 17 is above the needle plane 26 and the end of its part 210 is supported by the upper side of the fabric.

The holding down part 20b engages the fabric or the last row of stitches cast off shortly before the needles move from their rest position a, FIG. 3, through the knocking-over comb. Due to the inclined position of the part 2%, the row of stitches is presed downward so that the advancing needles cannot catch the stitches of this row. Subsequently part 200 becomes active, retaining the loop caught in the needle in front of the knocking-over comb, as the needle advances still further, and thereby opening the latch, until the needle reaches position 521 in which the respective loop slides completely over the opening latch and is pushed on to the shank of the needle. In the position 50 of the needles, part 200 remains practically inactive with regard to the knitting process, whereas when the needles move back into the initial position 5a, especially when the needles are withdrawn behind the knock ing-over comb 6, part 's pulls the fabric down and thus facilitates the casting oif of the new stitch.

If the cam device is pushed in the direction of the arrow A beyond the fabric, the two elements 16 and 17 swing into the rest position indicated by the dotted lines with reference to piece 17. When the movement of the carriage is reversed, the two elements turn in a clockwise direction until the stop 23 engages the notch b of member 19 and stop 22 engages the notch 24b of member 18; in this position element 17 takes over the holding down and retaining functions, while the end of the retaining part 200 of element v16 rests on top of the fabric and is pulled away over it.

Rocking of the two elements 16 and '17 is fully ensured without the aid of additional devices also if the direction of movement of the carriage 4 is reversed outside of the knitting Zone. Instead of the balanced position shown in dash-dot lines in FIG. 1 with respect to the element 17 when the machine is idling, a different position may be chosen, for example, by fitting a torsion spring to each element to determine the idling position of these elements.

The arms 20, 211 may be constructed in many different ways. The arms illustrated in FIGS. 5 and 6 are specially designed for knitting tubular fabric or similar work in which rows of stitches are formed on each individual bed separately or only on one of the two needle beds so that the pulling and retaining action must be effected directly at the knocking-over comb. In this case, the width of the ing-over combs and exerts a lateral pressure thereon, producing a pulling action at the needle beds at the point where it is most essential, namely, where the needles are withdrawn to the initial position 5a.

Whereas in the example shown in FIG. 5, the special .shape only aids the pulling action at the rear end of the pressure arm, in the example shown in FIG. 6 the retaining action at the front end of part 20c is increased, as this front part is split into two parts which are resiliently bent i outwards.

The example shown in FIG. 4 is specially designed for doing equilateral knitting, for example, borders or patent designs whereby needles from both beds knit the same article alternately. In this case, the top loop row is stretched between the two needle beds and intervention directly at the knocking-over comb is not required to obtain the retaining and pulling effect. It is suflicient that a pressure be exerted in the center of the upper loop row on the pressure arm. In the structure shown in FIG. 4, the retaining part consists of a substantially rigid, only slightly resilient rod 20d having a simple and smooth, for example cylindrical configuration with a diameter considerably smaller than the distance between the beds. This retaining part continues into a pulling down portion 20c which is considerably thinner and resilient, and produces a strong pulling effect when the needles are withdrawn to the initial position 5a.

The alternative shown in FIG. 7 diifers from that illustrated in FIGS. 1 and 2 in that the arm parts 200 and 210 are shorter and thus do not participate in the retaining action when the needles are withdrawn from position 50 to position 5a. In this version, the retaining elfect is produced by spring wire loops 30 and 31 which are secured to the rear of the support members 18 and 19 and are so dimensioned that the loop of the front or leading element in the direction of movement of the cam devices is outside of the needle zone, while the loop of the rear or trailing element is supported by the fabric where the needles are Withdrawn behind the knockingover comb. Therefore, the loop of the element which is trailing, depending on the direction of movement of the carriage, is active so that the pressure arms may be correspondingly shorter.

A further design of the pressure elements is illustrated in FIG. 9, in which only one end of the loop 30 is fastened to a support member, the other end being free and fitting into a corresponding recess 32 in the support member. The loop is not rounded as in FIG. 7, but angular.

As seen in FIG. 8, the short pressure arm in this case is split over its entire length so that two prongs 33 and 34 rest against the knocking-over combs, exerting a lateral pressure, similar to the variations shown in FIGS. 5 and 6.

With regard to the considerable alleviation in this case of the rotation of the pressure element upon reversal of the direction of movement of the cam device, the conditions are the same as in the example illustrated in FIG. 1.

I claim:

1. In a flat bed knitting machine for producing a knitted fabric, the machine having at least one oblong needle bed, a knocking-over comb connected to one long side of said needle bed, a plurality of juxtaposed parallel latch needles individually longitudinally movably supported by said bed, a knitted fabric supported by said needles, and cam means movably supported by said bed to move on said bed longitudinally thereof and transversely to thelongitudinal axes of said needles and adapted to engage and to advance said needles through said comb and to retract said needles to a position behind said comb upon movement of said cam means: a pressure device including support means connected to said cam means to move therewith, and two mirror-symmetric pressure elements spaced in the longitudinal direction of said bed and individually rotatably connected to said support means to rotate in a vertical plane, which is parallel to the direction of movement of said cam means and adjacent to said comb, and to rotate on axes at right angles to said plane and above said needle bed, each of said pressure elements including a resilient arm extending downward below the plane of said needle bed when the respective pressure element is beyond said fabric and the needles thereat are in retracted position.

2. In a fiat bed knitting machine as defined in claim 1, two stops connected to said support means for individually engaging said pressure elements and individually limiting rotation of said pressure elements in either direction of rotation.

3. In a fiat bed knitting machine as defined in claim 1 and wherein each of said pressure elements includes a resilient wire loop, the wire loop of the trailing pressure element extending into the plane of the needle bed, and the arm of the trailing pressure element being above the needle bed.

4. In a fiat bed knitting machine as defined in claim 1 and wherein each of said pressure elements includes a part which is rotatably connected to said support means and on which said resilient arm is made fast, and a resilient wire loop having one end made fast on said part, the latter having a recess receiving the second end of said wire loop, the wire loop of the trailing pressure element extending into the plane of the needle bed, and the arm of the trailing pressure element being above the needle bed.

5. In a fiat bed knitting machine as defined in claim 1 and wherein said arm includes a relatively rigid retaining portion and a resilient end part forming a pulling down portion which extends downward when said retaining portion is substantially parallel to the needle bed.

6. In a fiat bed knitting machine for producing a knitted fabric, the machine having two oblong needle beds having opposed long sides, parallel and spaced knocking-over combs individually connected to said opposed long sides, a plurality of juxtaposed parallel latch needles individually longitudinally movably supported by said beds, a knitted fabric supported by said needles, and cam means movably supported by said beds to move on said beds longitudinally thereof and transversely to the longitudinal axes of said needles and adapted to engage and advance said needles through said combs and to retract said needles to a position behind said combs upon movement of said cam means: a pressure device including support means connected to said cam means to move therewith, and two mirror-symmetric pressure elements spaced apart in the longitudinal direction of said beds and individually rotatably connected to said support means to rotate in a vertical plane extending between said combs and to rotate on axes at right angles to said plane, each of said pressure elements including a resilient arm extending downward between said combs and below the planes of said needle beds when the respective pressure element is beyond the fabric and the needles thereat are in retracted position, the width of said arms being substantially equal to the distance between said knocking-over combs.

7. In a flat bed knitting machine as defined in claim 6 and wherein at least a portion of said arms is longitudinally split and laterally resiliently urged against said combs.

References Cited in the file of this patent UNITED STATES PATENTS 2,715,328 Buhrer Aug. 16, 1955 FOREIGN PATENTS 207,494 Austria Feb. 10, 1960 

